how much would it cost to repair the engine motor

No way to provide a good estimate without a real world hands on assessment of your vehicle and engine concern. Unfortunately there is too wide a scale of possible causes and concerns to guess cost of repairs. Hello, when you say it overheated -- do you mean the temperature gauge went all the way up? Do you mean that the coolant boiled over? If you only drove a half mile, it sounds almost like a stuck thermostat. But it requires hands on testing to know for sure. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops